The plankton communities from peat bog pools: Structure, temporal variation and environmental factors

QUIROGA, MA. VICTORIA; UNREIN, FERNANDO; GONZÁLEZ GARRAZA, GABRIELA; KÜPPERS, GABRIELA; LOMBARDO, RUBÉN; MARINONE, MA. CRISTINA; MENU MARQUE, SILVINA; VINOCUR, ALICIA; MATALONI, GABRIELA

JOURNAL OF PLANKTON RESEARCH

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2013 vol. 35 p. 1234 - 1253

0142-7873

This is the first characterization of the structure and temporal variation of the plankton communities composing the complete food web in five peat bog pools as related to environmental factors; and was conducted over two consecutive ice-free periods in Tierra del Fuego (54°S). Remarkably, picophytoplankton was composed solely of eukaryotic cells, surpassing the dominance expectations for these acidic water bodies, while testaceans were virtually absent, even as tychoplankters. Abundances of the different planktonic communities were slightly higher than those reported for Northern Hemisphere peat bogs and humic lakes. Mixotrophic nutrition prevailed among nano- and microphytoplankters, a strategy also common in humic lakes. The spring structures of the planktonic communities from all studied pools were similar, whereas in late summer differences in the abundances and biomass of the different trophic compartments among small, shallow water bodies and large ones arouse, which seem to be dictated by distinct pool size-driven patterns of water temperature variation. A general shift in the control of heterotrophic flagellates abundance in the studied pools, turning from bottom-up regulation in spring to top-down control in late summer related to temperature dependant variations in zooplankton abundance and composition. Based on these evidences, we hypothesize that changes in the trophic interactions affecting the entire food web would occur over the open water period in these aquatic ecosystems, and that these would be dictated by pool morphometry and related abiotic features.